Means for controlling the movement of poppet valves



N. C. THUESEN Oct. 8, 1968 MEANS FOR CONTROLLING THE MOVEMENT OF POPPETVALVES Filed Dec. 18. 1967 INVENTOR IV/EL C THUESE/V ATTOF/Vf) UnitedStates Patent 3,404,666 MEANS FOR CONTROLLING THE MOVEMENT OF POPPETVALVES Niel C. Thuesen, 6021 Compton Ave., Los Angeles, Calif. 90001Filed Dec. 18,1967, Ser. No. 691,366 7 Claims. (Cl. 123-90 ABSTRACT OFTHE DISCLOSURE Compens ator means interposed between a poppet valve andthe cam-controlled mechanism that reciprocates the same, said meansincluding flexible means which, due to acceleration of the action ofsaid mechanism, flex so the poppet moves with increased velocity overthat of the tappet that carries it in the direction away from its seattoward open position, said poppet thereby moving greater distance thanthe tappet and being held open for a longer period of time due to theadditional movement of the poppet relative to the tappet.

Background of the invention In four-stroke cycle internal combustionengines, especially for automotive and aircraft use, the intake and exhaust valves are normally controlled, in their opening and closingmovements, by cam-controlled mechanisms having preset timed relation.The more accurately the open positions of the valve are timed, thegreater the general efiiciency' of operation of the engine as regardsfuel economy, and the cleaner the engine will run. Therefore, theexhaust of the gases of combustion will be less noxious, due to improvedcombustion, and engine performance will be materially improved. If suchpinpoint control of move ments of the valves is coupled with prolongedtime periods during which the valves remain open, further improvement incombustion efiiciency and general performance, as above, will result.

An object of the present invention is to provide improved compensatormeans by which the poppet valves of an internal combustion engine of thetype referred to are so controlled that theimprovements in performanceof such engines, as above enumerated, result.

Another object of the invention is to provide means of the' characterreferred to which, independently of the cam-controlled movements of thevalve-mounting tappet, allows for an additional further movement of thevalve poppets at the valve-open positions thereof.

The invention also has for its objects to provide such means that arepositive in operation, convenient in use, easily installed in a workingposition and easily disconnected therefrom, economical of manufacture,relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novelcombinations and arrangements of parts, which will more fully appear inthe course of the following description, which is based on theaccompanying drawing. However, said drawing merely shows, and thefollowing description merely describes, preferred embodiments of thepresent invention, which are given by way of illustration or exampleonly. I

The most pertinent art that may be cited comprises patents issued to theapplicant, as listed below: 3,183,901, May 1965; 3,185,139, May 1965;3,220,391, November 1965; 3,211,138, October '1965 (with C. H. Collins).

The above show various forms of compensators which are devised forallowing the poppet valves to seat properly. The same do not have anyteachings respecting the provision of means to provide the mentionedadded opening movement of the valves nor the pinpoint control of thevalve movement.

Summary of the invention The present improvements are incorporated in acylinder back 10 which is semidiagrammatically shown and has a cylinder11 and a flow port passage 12 leading to said cylinder with a valve seat13 where said passage 12 joins said cylinder 11. Since, in four-strokecycle engines, each cylinder is provided with at least one inlet and oneoutlet port, said passage 12 is representative of each such port. In anexemplary manner, a camshaft 14 reciprocates a tappet 15 that is guidedfor movement in aligned guides 16 mounted on the cylinder block, throughthe medium of a mechanism 17. A poppet valve 18, in the usual manner, ismounted in said cylinder block 10 to reciprocate and move between aposition engaged with the seat 13 to close the port passage 12, and aposition spaced therebelow to open said passage. According to theinvention, the present poppet-controlling means 19 is carried by theupper end of the poppet stem 20 and is engaged by the tappet 15.

Brief description of the drawing In the drawing, like referencecharacters designate similar parts in the several views.

FIGS. 1, 2 and 3, in semidiagram-matic form, show three successivepositions of the poppet valve and the means controlling the movementthereof.

FIGS. 4, 5 and 6, to an increased scale, show the compensator means andthe respective operative positions thereof according to FIGS. 1, 2 and3.

FIG. 7, to the same scale, is a plan view of the compensator means,partly in section to show detail.

FIG. 8, to a further increased scale, shows a modification of thecompensator means.

Description of the preferred embodiments The camshaft 14 is shown with acam lobe that operates the mechanism 17. The latter is shown as having alifter 26 which may be a hydraulic lifter for obtaining uniformoperation during all engine speeds, a rod 27 connected by a pivot 28 tothe upper end of said lifter, a spring abutment 29 on said rod, acompression spring 30 around said rod with one end engaged with saidabutment 29 and the opposite end engaged with a fixed abutment 31 on thecylinder block, a rocker arm 32 on a rocker shaft 33 having one armthereof pivotally connected to the upper end of the rod 27, and a link34 pivotally connected by one end to an oppositely extending arm of therocker arm 32, the other end of said link being shown as pivotallyconnected to the tappet 15.

While FIGS. 1, 2 and 3 show the rod .27 and the axis of the poppet valve18 parallel, these parts may be arranged so there is an inclined angletherebetween. Irrespective of the chosen arrangement of the partsconstituting the mechanism 17, the cam lobe 25, on its rising movement,moves the tappet 15 from its raised position of FIG. 1 to its lowermostposition of FIG. 3, when it is at top dead center. This movement iseffected against the light bias of the spring 30 and causes the tappetto move a distance represented by the dimension 35 (FIG. 3). In theabsence of means on the camshaft 14 to reverse this movement of 3 themeans 17, the spring 30 performs this function upon continued rotationof said camshaft.

The present poppet movement-controlling means 19 is shown as disposed ina space 36 in the tappet between an upper wall 37 and transverselyspaced ledges 38, the same constituting opposed abutments. Said means 19is shown as comprising a body 39 preferably having a polygonal forminthis case, eight-sided and a lower frusto-conical portion 40, the wallof which is convex as viewed from above. A central or axial opening 41in said portion has clearance around the stem of the valve 18 whichextends upwardly therethrough.

A complement of flexible elements 42 is disposed within the body 39, thenumber thereof preferably conforming to and fitting against the sidefaces of said body, said elements 42, as seen in FIG. 7, being clear ofeach other so each may flex independently of its adjacent elements. Saidelements may be flat, or may have some degree of initial flexureimparted thereto. Also, as shown in FIG. 8, instead of a single layer ofelements as in FIGS. 4, 5 and 6, two or more layers 42a may be used. Thetop layer may be flat and the others therebelow may be initially curvedor bent to varying degrees so the spring rate of the elements may beinterchanged for obtaining the rate of operative movement of the valveas desired.

A member 43 having a central hole for the valve stem 20 is disposed uponsaid flexible elements 42 and has a lower conical portion having aconcave face 44 that cooperates with the convex conical wall 40 to causeflexure of said elements when said body 39 and member 43 are movedtoward each other during operation. As shown in FIG. 6, the face 44 ispreferably formed to have polygonal sides that have transverselycoextensive engagement with the elements 42.

A cover member 45 has a peripheral portion 46 that rests upon the outerportions of said elements 42 or 42a and is clamped thereagainst by aspunover rim 47 of the body. Said cover member 45 circumscribes member43 so as to allow relative longitudinal movement of the latter memberand the cover-provided body 39. An inturned flange 48 on the upper endof the cover member 45 limits such relative movement.

A nut 49 is threadedly engaged with the upper end of the valve stem 20and forms retainer means preventing the member 43 from becomingseparated from the valve. An abutment end 50 is provided on said nut.

Operation When the cam lobe is in the low position of FIG. 1, the returnspring holds the tappet 15 raised to its maximum high position, asindicated by the arrow 51. From FIGS. 1 and 4, it will be seen that inthis position, the valve 18 is retained against its seat 13 and that thetappet wall 37 is spaced from the abutment extension 50. Since theupward resilient bias on the tappet 15 causes the body 39 of the means19 to seat firmly on the ledges 38, and the valve 18 is held fixedlyagainst its seat, the normally unflexed elements 42 will flex to thecondition of FIG. 4.

Now, when the cam lobe 25 rises, as in the position of FIG. 2, theinitial downward movement of the tappet 15 will move its wall 36 towardthe abutment extension 50, thus releasing the flexure imposed by themember 43 on the elements 42, and permitting the latter to flatten outas in FIG. 5. For the initial part of this movement, the tappet movesdownwardly but the poppet valve 18 remains seated. Thus, in effect thepoppet valve has become shorted by such straightening of the elements42.

Then, because there now is a direct contact between the tappet wall 37and the poppet valve 18, the rapidly accelerated movement of the former,as the cam lobe 25 moves from its relatively low angular position ofFIG. 2 toward its top dead center position of FIG. 3, causes the valve18, under this impact, to accelerate, according to the arrow 52, andhave increased velocity, causing the valve to move back to its initialrelationship with the parts of the means 19 as in FIG. 1, and again flexthe elements 42. As a consequence, the opening between the valve and thevalve seat, shown by the dimension 53, is greater than the dimension 35,which represents the full tappet movement, less the initial movement ofthe tappet from its fully raised position of FIG. 1 to the position ofFIG. 2 where the encounter of the tappet wall 37 and the abutmentextension 50 occurs.

Such controlled acceleration of the poppet movement, causing the valveto remain open longer than if directly moved by the mechanism 17,enables pinpoint opening of the valve, induces eflicient and cleanerengine performance, improved timing of fuel inlet and exhausting ofburnt gases, and generally increases efliciency of engine operation.

While the foregoing has illustrated and described what is nowcontemplated to be the best mode of carrying out the invention, theconstructions are, or course, subject to modification without departingfrom the spirit and scope of the invention. Therefore, it is not desiredto restrict the invention to the particular forms of constructionillustrated and described, but to cover all modifications that may fallwithin the scope of the appended claims.

Having thus described the invention, what is claimed and desired to besecured by Letters Patent is:

1. In means for controlling the reciprocative movement of a poppet valveand in which a tappet for said valve is reciprocated at a velocity thatis greatest when approaching valve-opening position, said valvecontrolling flow between a cylinder and a flow port with a valve seatprovided where said port and cylinder join, the tappet being providedwith opposed abutments, means disposed in the space in said tappetbetween said opposed abutments to control axial movement of the poppetvalve, said means comprising:

(a) a member mounted adjacent the upper end of the stem of the poppetvalve and provided with a frustoconical portion having a concave face,

(b) a housing around said member and having a convex frusto-conicalportion generally conforming to the corresponding portion of thementioned member, said housing being engaged with one of the mentionedabutments on the tappet and disposed in the mentioned space in thetappet,

(c) a complement of flexible elements within said housing with theirouter portions fixedly held therein and the portions directed toward theaxis of the valve stem free to flex when engaged from opposite sidesbysaid frusto-conical portions of the member and the housing, and

(d) an abutment on the end of the valve stem beyond the member havingthe frusto-conical portion with the concave face,

(e) said end abutment on the valve stem being retained in resilientcontact with the tappet abutment that is opposite to the one engagedwith the housing,

(f) said poppet valve, while in contact with the lastmentioned tappetabutment, under the mentioned increased acceleration of the tappet,being propelled at an increased velocity which causes flexure of theflexible elements and a movement of the poppet valve that is greaterthan that of the tappet, thereby increasing the opening to flow betweenthe cylinder and the port passage.

2. In valve movement-controlling means according to claim 1, thementioned flexible elements being arranged in a single layer thereof.

3. In valve movement-controlling means according to claim 1, thementioned flexible elements being arranged in plural layers with thelayer engaged with the frustoconical portion of the housing beinginitially curved more than are the elements in the other layers.

4. In a valve movement-controlling means according to claim 3, theintermediate layers of flexible elements being curved to lesser degreesas the least curved layer is approached.

5. In a valve movement-controlling means according to claim 1, thehousing having a polygonal outer form and the flexible elements havingportions fitting against and extending radially from the outer wall ofthe housing.

6. In a valve movement-controlling means according to claim 5, a clampmember cooperating with the polygonal wall of the housing to clamp theadjacent outer portions of the flexible elements so the ports of thelatter adjacent the axis may flex.

7. In a valve movement-controlling means according to claim 1, thementioned abutment end being threadedly connected to the end of thetappet stem and constituting a retainer member to hold the member withthe concave face in assembly on the valve stem.

References Cited UNITED STATES PATENTS 3,183,901 5/1965 Thuesen 123-903,135,139 5/1965 Thuesen 123 90 3,211,138 10/1965 Collins et al 123 9010 3,220,391 11/1965 Thuesen 123-90 AL LAWRENCE SMITH, Primary Examiner.

